Technical Abstract:
To gain a better understanding of the aspects underlying normal and growth hormone enhanced growth in salmonids, quantitative expression analysis was performed for a number of genes related to muscle growth, metabolism, immunology and energy regulation. This analysis was performed in liver and muscle tissue in wild-type coho salmon (Oncorhynchus kisutch), domesticated coho salmon selected for growth, growth hormone-transgenic coho salmon fed to satiation, and growth hormone-transgenic coho salmon reared on restricted rations and in 5 strains of rainbow trout (Oncorhynchus mykiss) including wild-type fish, domesticated fish and 2 groups of fish from both of these same strains that each transgenically expressed growth hormone at low and at high levels. There were several growth related genes that showed similar expression levels in domesticated and full-fed fish. However, distinct differences were noted between wild-type, domesticated and transgenic fish for genes involved with muscle cell differentiation, innate immunity, metabolism and amino acid regulation. Comparison studies of transgenic and non-trangenic animals under different planes of nutrition provide excellent models for studying specific growth and nutrient interactions.